Singapore Airlines has changed the seatbelt sign rules in a more tightening of cabin-service norms after a recent turbulence killed one passenger and injured many, media reports said.

The airline said it is taking a "more cautious approach" to manage a similar turbulence.

The airline stated hot drinks will be suspended and in-flight meal service will be stopped if the seatbelt sign is on.

The crew members will also have to sit in their seats with belts on.

The airline "will continue to review our processes", it says.

One person died and several others were injured after a Singapore Airlines flight from London encountered severe turbulence on Tuesday.

The flight was on its way from London to Singapore.

Singapore Airlines CEO issues public apology

"Our deepest apology to everyone affected by this incident," CEO Goh Choon Phong said in a video statement.